path: root/Documentation/media-framework.txt
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2013-02-08[media] Documentation/media-framework.txt: fix a sentenceAntonio Ospite
Signed-off-by: Antonio Ospite <> Signed-off-by: Mauro Carvalho Chehab <>
2012-05-14[media] media: Add link_validate() op to check links to the sink padSakari Ailus
The purpose of the link_validate() op is to allow an entity driver to ensure that the properties of the pads at the both ends of the link are suitable for starting the pipeline. link_validate is called on sink pads on active links which belong to the active part of the graph. Signed-off-by: Sakari Ailus <> Acked-by: Laurent Pinchart <> Signed-off-by: Mauro Carvalho Chehab <>
2011-09-27doc: fix broken referencesPaul Bolle
There are numerous broken references to Documentation files (in other Documentation files, in comments, etc.). These broken references are caused by typo's in the references, and by renames or removals of the Documentation files. Some broken references are simply odd. Fix these broken references, sometimes by dropping the irrelevant text they were part of. Signed-off-by: Paul Bolle <> Signed-off-by: Jiri Kosina <>
2011-07-27[media] v4l: Fix minor typos in the documentationSylwester Nawrocki
Signed-off-by: Sylwester Nawrocki <> Signed-off-by: Mauro Carvalho Chehab <>
2011-03-31Fix common misspellingsLucas De Marchi
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <>
2011-03-22[media] media: Pipelines and media streamsLaurent Pinchart
Drivers often need to associate pipeline objects to entities, and to take stream state into account when configuring entities and links. The pipeline API helps drivers manage that information. When starting streaming, drivers call media_entity_pipeline_start(). The function marks all entities connected to the given entity through enabled links, either directly or indirectly, as streaming. Similarly, when stopping the stream, drivers call media_entity_pipeline_stop(). The media_entity_pipeline_start() function takes a pointer to a media pipeline and stores it in every entity in the graph. Drivers should embed the media_pipeline structure in higher-level pipeline structures and can then access the pipeline through the media_entity structure. Link configuration will fail with -EBUSY by default if either end of the link is a streaming entity, unless the link is marked with the MEDIA_LNK_FL_DYNAMIC flag. Signed-off-by: Laurent Pinchart <> Acked-by: Hans Verkuil <> Signed-off-by: Mauro Carvalho Chehab <>
2011-03-22[media] media: Links setupLaurent Pinchart
Create the following ioctl and implement it at the media device level to setup links. - MEDIA_IOC_SETUP_LINK: Modify the properties of a given link The only property that can currently be modified is the ENABLED link flag to enable/disable a link. Links marked with the IMMUTABLE link flag can not be enabled or disabled. Enabling or disabling a link has effects on entities' use count. Those changes are automatically propagated through the graph. Signed-off-by: Laurent Pinchart <> Signed-off-by: Stanimir Varbanov <> Signed-off-by: Sakari Ailus <> Acked-by: Hans Verkuil <> Signed-off-by: Mauro Carvalho Chehab <>
2011-03-22[media] media: Entity use countLaurent Pinchart
Due to the wide differences between drivers regarding power management needs, the media controller does not implement power management. However, the media_entity structure includes a use_count field that media drivers can use to track the number of users of every entity for power management needs. The use_count field is owned by media drivers and must not be touched by entity drivers. Access to the field must be protected by the media device graph_mutex lock. Signed-off-by: Laurent Pinchart <> Acked-by: Hans Verkuil <> Signed-off-by: Mauro Carvalho Chehab <>
2011-03-22[media] media: Entity graph traversalSakari Ailus
Add media entity graph traversal. The traversal follows enabled links by depth first. Traversing graph backwards is prevented by comparing the next possible entity in the graph with the previous one. Multiply connected graphs are thus not supported. Signed-off-by: Sakari Ailus <> Signed-off-by: Laurent Pinchart <> Signed-off-by: Vimarsh Zutshi <> Acked-by: Hans Verkuil <> Signed-off-by: Mauro Carvalho Chehab <>
2011-03-22[media] media: Entities, pads and linksLaurent Pinchart
As video hardware pipelines become increasingly complex and configurable, the current hardware description through v4l2 subdevices reaches its limits. In addition to enumerating and configuring subdevices, video camera drivers need a way to discover and modify at runtime how those subdevices are connected. This is done through new elements called entities, pads and links. An entity is a basic media hardware building block. It can correspond to a large variety of logical blocks such as physical hardware devices (CMOS sensor for instance), logical hardware devices (a building block in a System-on-Chip image processing pipeline), DMA channels or physical connectors. A pad is a connection endpoint through which an entity can interact with other entities. Data (not restricted to video) produced by an entity flows from the entity's output to one or more entity inputs. Pads should not be confused with physical pins at chip boundaries. A link is a point-to-point oriented connection between two pads, either on the same entity or on different entities. Data flows from a source pad to a sink pad. Links are stored in the source entity. To make backwards graph walk faster, a copy of all links is also stored in the sink entity. The copy is known as a backlink and is only used to help graph traversal. The entity API is made of three functions: - media_entity_init() initializes an entity. The caller must provide an array of pads as well as an estimated number of links. The links array is allocated dynamically and will be reallocated if it grows beyond the initial estimate. - media_entity_cleanup() frees resources allocated for an entity. It must be called during the cleanup phase after unregistering the entity and before freeing it. - media_entity_create_link() creates a link between two entities. An entry in the link array of each entity is allocated and stores pointers to source and sink pads. When a media device is unregistered, all its entities are unregistered automatically. The code is based on Hans Verkuil <> initial work. Signed-off-by: Laurent Pinchart <> Signed-off-by: Sakari Ailus <> Acked-by: Hans Verkuil <> Signed-off-by: Mauro Carvalho Chehab <>
2011-03-22[media] media: Media deviceLaurent Pinchart
The media_device structure abstracts functions common to all kind of media devices (v4l2, dvb, alsa, ...). It manages media entities and offers a userspace API to discover and configure the media device internal topology. Signed-off-by: Laurent Pinchart <> Acked-by: Hans Verkuil <> Signed-off-by: Mauro Carvalho Chehab <>